Method and device for cutting braking surfaces of a brake rotor

ABSTRACT

A cutting method which can efficiently cut braking surfaces of a brake rotor of a wheel bearing assembly. A reference surface on one side of a vehicle body-mounting flange provided on an outer member of the wheel bearing assembly is brought into abutment with positioning pieces of a positioning member, and a cylindrical outer peripheral surface of the outer member is clamped by a chuck device. By advancing pushrods of first and second pressing devices, a raceway member and a hub ring forming the inner member are pressed axially to put the assembly into an actual mounted state. The inner member and the brake rotor are rotated by rotating the pushrod of the second pressing device, and a cutting tool is moved in a direction parallel to the reference surface to cut the braking surfaces of the brake rotor.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a method and a device for cuttingbraking surfaces of a brake rotor mounted on a wheel-mounting flange ofa wheel bearing assembly.

[0002] Among wheel bearing assemblies, there are ones for driving wheelsand ones for non-driving wheels. FIG. 3 shows one example. This wheelbearing assembly is for a driving wheel, and comprises an outer member1, an inner member 2 and double-row rolling elements 3 mounted betweenthe outer and inner members 1 and 2.

[0003] A vehicle body-mounting flange 4 is formed on the outer peripheryof the outer member 1, and double-row raceways 5 are formed on its innerperiphery.

[0004] The inner member 2 comprises a hub ring 2 a as a first rotarymember and a raceway member 2 b as a second rotary member. On the outerperiphery of the hub ring 2 a, a wheel-mounting flange 6 and a raceway 7opposing one of raceways 5 formed on the outer member 1 are formed. Hubbolts 8 are provided on the wheel-mounting flange 6. A wheel pilot 9 isformed at one end of the hub ring 2 a, while a small-diameter portion 10is provided at the other end. A spline hole 11 extends therethrough fromits small-diameter portion 10 to the bottom of the wheel pilot 9.

[0005] The raceway member 2 b is fitted on the small diameter portion 10of the hub ring 2 a, and is formed on its outer periphery with a raceway12 opposing the other of the double-row raceways 5 formed on the outermember 1.

[0006]6 The double-row rolling elements 3 are mounted between thedouble-row raceways 5 formed on the inner periphery of the outer member1 and the raceways 7 and 12 formed on the hub ring 2 a and the racewaymember 2 b, respectively, to support the inner member 2 rotatablyrelative to the outer member 1. Also, seals S are mounted at both endsof the space between opposing surfaces of the outer member 1 and theinner member 2 to prevent entry of dust into the interior.

[0007] With the wheel bearing assembly having the abovesaid structure,in mounting to a vehicle, the vehicle body-mounting flange 4 formed onthe outer member 1 is mounted to the vehicle body by tightening bolts.

[0008] Also, a spline shaft provided on an outer joint member of aconstant-velocity joint is inserted into the spline hole 11 formed inthe hub ring 2 a, a nut is brought into threaded engagement with athreaded shaft formed at the tip of the spline shaft, and the nut istightened with a predetermined torque to press the hub ring 2 a and theraceway member 2 b against each other to impart a preload between therolling elements and the raceways 5, 7 and 12.

[0009] Further, wheel nuts 14 are threaded onto the hub bolts 8 providedon the wheel-mounting flange 6 and they are tightened to mount a brakerotor 13 and vehicle wheel to the wheel-mounting flange 6.

[0010] With such a wheel bearing assembly, because runout of the brakingsurface 13 a during rotation of the brake rotor 13 can be a cause ofbrake judder during braking, high machining accuracy and highdimensional accuracy are required for the parts of the wheel bearingassembly.

[0011] But even if the machining accuracy of each part is increased,since machining errors of the respective parts accumulate duringassembly of the wheel bearing assembly and also assembling errorsdevelop, it is impossible to suppress run-out of the braking surface 13a of the brake rotor 13.

[0012] In order to solve this problem, a cutting method has already beenproposed in which a wheel bearing assembly is assembled so as to beactually mountable, and a wheel bearing assembly with a brake rotormounted to a wheel-mounting flange 6 provided on the inner member 2 ismounted on a cutting machine, and the braking surface 13 a of the brakerotor 13 is cut while rotating the inner member 2 and the brake rotor 13(Japanese patent publication 11-19803).

[0013] According to this cutting method, since the braking surface 13 aof the brake rotor 13 is cut with the wheel bearing assembly with thebrake rotor in an actually mounted state, accumulated errors in whichmachining errors of the respective parts accumulate, and strainsproduced in mounting the brake rotor 13 are removed. Thus, by mountingthe wheel bearing assembly with the brake rotor thus cut on an actualvehicle, the wheel bearing assembly is restored to the state at the endof cutting, so that run-out of the braking surface 13 a during rotationof the brake rotor 13 is extremely small. Thus it is possible to rotatethe brake rotor 13 with extremely high accuracy.

[0014] In the above method, in which the braking surfaces 13 a of thebrake rotor 13 are cut in an actual mounted state, a spline shaftprovided at the tip of a drive shaft is inserted into a spline hole 11formed in the inner member 2, a pre-load nut is threaded onto a threadedshaft provided at the tip of the spline shaft, and the pre-load nut istightened to make the wheel bearing assembly in an actual mounted state.Thus, attaching and detaching of the wheel bearing assembly with thebrake rotor are extremely troublesome and it takes a long time forcutting.

[0015] An object of this invention is to provide a method for cuttingbraking surfaces of a brake rotor of a wheel bearing assembly whichmakes it possible to efficiently cut the braking surfaces of the brakerotor in a short time by making it possible to easily put the wheelbearing assembly in an actual mounted state, and a device therefor.

SUMMARY OF THE INVENTION

[0016] According to this invention, there is provided a method ofcutting braking surfaces of a brake rotor of a wheel bearing assembly,the assembly comprising an outer member having a vehicle body-mountingflange on its outer periphery, an inner member having a wheel-mountingflange on its outer periphery, rolling elements disposed between theouter member and the inner member for rotatably supporting the innermember, and the brake rotor which is mounted to the wheel-mountingflange of the inner member, comprising the steps of assembling the wheelbearing assembly with the brake rotor in an actual mounted state,determining a mounting surface of the vehicle bodymounting flange to bemounted on a vehicle body as a reference surface, non-rotatablysupporting the outer member positioned against the reference surface,clamping the inner member with a pair of oppositely arranged pressingmembers from both ends thereof with a pressing force corresponding tothe clamping force in the actual mounted state, rotating the innermember and the brake rotor while maintaining the clamped state, andcutting the braking surfaces of the brake rotor by moving a cutting toolin a direction parallel to the reference surface.

[0017] With this arrangement, since the wheel bearing assembly with thebrake rotor can be brought into an actual mounted state by non-rotatablysupporting the outer member while positioning it against the referencesurface on the vehicle body-mounting flange formed on the outer member,and pressing the inner member with a pair of pressing devices from bothaxial ends, it is possible to efficiently perform cutting of the brakingsurfaces of the brake rotor.

[0018] By using dry-cutting with no cutting liquid for cutting by thecutting tool, and cutting the braking surfaces of the brake rotor whilesupplying compressed air from one end of the outer member so that thecompressed air flows along the outer periphery of the outer member, itis possible to prevent chip produced by cutting from adhering to theseals of the wheel bearing assembly and avoid damage to the seals.

[0019] Also, by performing cutting of the braking surfaces while suckingchip, it is possible to reliably prevent chip from adhering to the sealsof the wheel bearing assembly and avoid damage to the seals, andscattering of chip to the surroundings.

[0020] According to this invention, there is also provided a cuttingdevice for cutting braking surfaces of a brake rotor mounted on a wheelbearing assembly, the wheel bearing assembly comprising an outer memberhaving a vehicle body-mounting flange on its outer periphery, thevehicle body-mounting flange having a mounting surface to a vehicle bodyas a reference surface, an inner member having a wheel-mounting flangeon its outer periphery, and rolling elements disposed between the outermember and the inner member, the cutting device comprising a positioningmember for positioning the reference surface on the vehiclebody-mounting flange of the outer member, a chuck device for clampingthe outer member, a pair of pressing devices for pressing and clampingthe inner member from both ends thereof with a pressing forcecorresponding to the clamping force in an actual mounted state, a rotarydevice for rotating the inner member, and a tool rest carrying a cuttingtool for cutting the braking surfaces of the brake rotor and mounted soas to be movable in a direction parallel to the reference surface on thevehicle body-mounting flange of the outer member.

[0021] With this arrangement, by clamping the outer member with thechuck device with the reference surface of the vehicle body-mountingflange provided on the outer member in abutment with the positioningmember, and pressing the first and second rotary members with a pair ofpressing devices from both sides, it is possible to put the wheelbearing assembly with the brake rotor in an actual mounted state. And,by rotating the inner member with the rotary means and radially inwardlymoving the tool rest from the outer periphery of the brake rotor, it ispossible to cut the braking surfaces of the brake rotor.

[0022] Since a cutting tool comprising a pair of tool holder eachcarrying a cutter for cutting the braking surfaces, and fixing one ofthe pair of tool holders to the cutter rest while supporting the othertool holder so as to be openable and closable relative to the one toolholder, the distance between the pair of cutters can be adjusted. Thus,it is possible to arbitrarily adjust the amount of cut into the brakingsurfaces of the brake rotor. Also, because after cutting of the brakingsurface, the cutting tool can be returned to the original position atthe start of machining with the tool holder open, it is possible toprevent it from damaging the braking surfaces of the brake rotorsubjected to cutting.

[0023] By providing the cutting device according to this invention withan air supply means for supplying compressed air from one end of theouter member along its outer periphery, or a suction means for suckingand removing chip formed by cutting, it is possible to solve a problemthat cutting powder adheres to the seals of the wheel bearing assemblyand imparts damage to the seals.

[0024] Other features and objects of the present invention will becomeapparent from the following description made with reference to theaccompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]FIG. 1 is a plan view showing an embodiment of a cutting deviceaccording to this invention;

[0026]FIG. 2 is a partially enlarged sectional plan view of the same;

[0027]FIG. 3 is a vertical sectional front view showing one example ofwheel bearing assembly with a brake rotor;

[0028]FIG. 4 is a similar view showing another example of the same; and

[0029]FIG. 5 is a sectional view of an attachment for driving the wheelbearing assembly shown in FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0030] Hereinbelow, an embodiment of this invention will be describedwith reference to the drawings.

[0031] As shown in FIG. 1, the cutting device embodying the presentinvention has a first support member 21 and a second support member 22arranged opposite to the first support member 21.

[0032] On the side of the first support member 21, a chuck device 23 forclamping an outer member 1 of the wheel bearing assembly A with a brakerotor shown in FIG. 3, and a first pressing device 24 for axiallypressing a raceway member 2 b of an inner member 2 are provided.

[0033] On the side of the second support member 22, a second pressingdevice 25 for axially pressing a hub ring 2 a of the inner member 2 ofthe wheel bearing assembly A is provided.

[0034] As shown in FIG. 2, the chuck device 23 comprises a tubularcollet holder 26 having its rear end supported on the first supportmember 21, a spring collet 27 mounted in the collet holder 26, and adrawbar 28 for axially moving the spring collet 27.

[0035] The drawbar 28 has a connecting shaft 28 c coupled to the tip ofa tubular member 28 a through a connecting tube 28 b, which is slidablyinserted in a guide hole 29 formed in the first support member 21.

[0036] A protrusion 31 is formed on the outer periphery of theconnecting shaft 28 c at its tip. The protrusion 31 engages in anannular groove 32 formed in the inner peripheral surface of the springcollet 27 at its rear end.

[0037] With this chuck device 23, the spring collet 27 is moved back andforth by the axial movement of the drawbar 28. During retraction of thespring collet 27, a tapered surface 33 formed on the inner surface ofthe collet holder 26 at its tip and a tapered surface 34 formed on theouter peripheral surface of the spring collet 27 at its tip will bebrought into contact with each other to shrink the tip of the springcollet 27, thereby chucking the cylindrical outer peripheral surface ofthe outer member 1.

[0038] In the spring collet 27, a support ring 35 and a positioningmember 36 are mounted. The support ring 35 has a plurality of legs 37.Each leg 37 is fixed to an end plate of the collet holder 26 by screws.

[0039] The positioning member 36 is provided with a plurality ofpositioning pieces 36 b on the outer periphery of an annular plate 36 afixed to the support ring 35 by screws. Each positioning piece 36 b isinserted in an axial groove 38 formed in the inner periphery of thespring collet 27 and has its tip protruding outwardly from the tip ofthe spring collet 27.

[0040] The wheel bearing assembly A shown in FIG. 3 has a brake rotor 13mounted by tightening nuts 14 in threaded engagement with hub bolts 8with a predetermined torque. The vehicle body mounting surface 4 a of avehicle body-mounting flange 4 of the wheel bearing assembly A is areference surface 4 a. By pressing the reference surface 4 a against thetips of the positioning pieces 36 b of the positioning member 36, thewheel bearing assembly A with a brake rotor is positioned.

[0041] In the support member 21 and the connecting shaft 28 c of thedrawbar 28, an air supply passage 39 is formed so as to communicate withthe interior of the spring collet 27. When compressed air is suppliedinto the spring collet 27 through the air supply passage 39, it flowsalong the outer peripheral surface of the outer member 1 clamped by thespring collet 27, and flows out through the opposed surfaces of thespring collet 27 and the wheel-mounting flange 6.

[0042] As shown in FIG. 1, the first pressing device 24 has a jointmember 41 connected to a piston rod 40 a of a cylinder 40, and a pushrod43 having its rear end rotatably supported by a bearing 42 mounted inthe joint member 41. The pushrod 43 is moved back and forth by thecylinder 40 to press the raceway member 2 b of the wheel bearingassembly A when advancing.

[0043] The second pressing device 25 has a support tube 45 slidablyinserted in a guide hole 44 formed in the second support member 22, asupport plate 46 having its one end fixed to the rear end of the supporttube 45 and its other end supported so as to be slidable along a guideshaft 47 provided on the second support member 22, and a cylinder 48fixed to the support plate 46 and having a piston rod 48 a fixed to thesecond support member 22 to move the support tube 45 back and forth bythe cylinder 48.

[0044] Also, a bearing 49 is mounted in the support tube 45 as shown inFIG. 2 to rotatably support a pushrod 50 so as to move back and forthtogether with the support tube 45. While advancing, the pushrod 50axially presses the end face of the wheel pilot 9 formed on the hub ring2 a of the wheel bearing assembly A by its tip.

[0045] The pushing force with which the pushrod 43 of the first pressingdevice 24 and the pushrod 50 of the second pressing device 25 axiallypress the raceway member 2 b and the hub ring 2 a, respectively, ispreset at a force which is substantially equal to the clamping force forclamping the raceway member 2 b and the hub ring 2 a when the wheelbearing assembly A is in the actually mounted state.

[0046] At the tip of the pushrod 50 in the second pressing device 25, arotor pressing device 51 is provided to axially press the brake rotor 13mounted to the wheel-mounting flange 6 of the inner member 2 of thewheel bearing assembly. The rotor pressing device 51 has a pressingmember 52 slidably fitted on the tip of the pushrod 50, a key 53 mountedon the pushrod 50 to prevent the pressing member 52 from rotating, asnap ring 54 and a stopper plate 55 mounted to the tip of the pushrod 50for restricting the amount of sliding motion of the pressing member 52.The stopper plate 55 is axially position-adjustable by a nut 57 inthread engagement with male threads 56 formed on the outer periphery ofthe pushrod 50.

[0047] Also, an axial hole 58 is formed in the pressing member 52, and apin 59 and a spring 60 for biasing the pin 59 toward the stopper plate55 are mounted in the hole 58. While the pushrod 50 is advancing, thepressing member 52 is advanced together with the pushrod 50 to bring itinto abutment with the brake rotor 13. Further advancement of thepushrod 50 relative to the pressing member 52, which is now retained ina stopped state, causes the stopper plate 55 to push the pin 59 anddeforms the spring 60, thereby pressing the brake rotor 13 by theresilience of the spring 60.

[0048] The inner member 2, which is now pressed from both axial ends bythe pushrods 43 and 50 of the first pressing device 24 and the secondpressing device 25, is rotated by a rotary device 61 provided on theside of the second support member 22 (FIG. 1).

[0049] As shown in FIGS. 1 and 2, the rotary device 61 comprises a motor62 connected to the rear end of the pushrod 50 in the second pressingdevice 25, and a spline shaft 63 mounted to the tip of the pushrod 50 soas to be engageable in the spline hole 11 of the hub ring 2 a of thewheel bearing assembly A. The spline shaft 63 is inserted into thespline hole 11 while the pushrod 50 is advancing so that the pushrod 50will be rotated by the motor 62.

[0050]FIG. 1 shows a state in which the wheel bearing assembly A hasbeen mounted. A tool rest 64 is provided on one side of the outerperiphery of the brake rotor 13.

[0051] The tool rest 64 is movable in parallel to the reference surface4 a formed on the vehicle body-mounting flange 4 of the outer member 1.On the tool rest 64, a cutting tool 65 for cutting braking surfaces 13 aon both sides of the brake rotor 13 is supported.

[0052] The cutting tool 65 comprises a pair of tool holders 67 a and 67b having cutters 66 mounted at their tips. One tool holder 67 a is fixedto a base 68 mounted to one side of the tool rest 64, while the othertool holder 67 b is supported on a slider 71 which is movable along aslide base 70 of a linear slide 69, and arranged opposite to the fixedtool holder 67 a.

[0053] The slide base 70 is fixed to a support plate 72 mounted to oneside of the tool rest 64. The slider 71 is moved along the slide base 70as a threaded shaft 74 a of a ball screw 74 is rotated driven by a motor73. By the movement of the slider 71, the distance between the pair ofcutters 66 is adjustable.

[0054] The cutting device embodying the present invention has theabove-described structure. In cutting the braking surfaces of the brakerotor 13 of the wheel bearing assembly A shown in FIG. 3, the outermember 1 of the wheel bearing assembly is inserted into the springcollet 27 of the chuck device 23 shown in FIG. 2, and the referencesurface 4a formed on the vehicle body-mounting flange 4 is brought intoabutment with the tips of the positioning pieces 36b of the positioningmember 36 to position the outer member 1.

[0055] After positioning the outer member 1, the drawbar 28 is retracted(leftwardly in FIG. 2) to shrink the spring collet 27 by the movement ofthe tapered surface of the spring collet 27 relative to the taperedsurface 33 of the collect holder 26, thereby clamping the cylindricalouter peripheral surface of the outer member 1.

[0056] After clamping the outer member 1, the respective pushrods 43 and50 of the first pressing device 24 and second pressing device 25 areadvanced to press the end face of the raceway member 2 b with thepushrod 43 of the first pressing device 24 and press the wheel pilot 9of the hub ring 2 a with the pushrod 50 of the second pressing device25, thereby clamping the hub ring 2 a and the raceway member 2 b with apressing force which is substantially equal to the clamping force in theactual mounted state.

[0057] While the pushrod 50 of the second pressing device 25 isadvancing, the spline shaft 63 provided at the tip of the pushrod 50 isinserted into the spline hole 11 formed in the hub ring 2 a.

[0058] Before the tip of the pushrod 50 presses the end face of thewheel pilot 9, the pressing member 52 provided at the tip of the pushrod50 abuts the side of the brake rotor 13 and stops. As the pushrod 50further advances relative to the pressing member 52, which is retainedin the stopped state, the spring 60 will be resiliently deformed. Due tothe restoring resilience of the spring, the pressing member 52 pressesone side of the brake rotor 13.

[0059] After the wheel bearing assembly with the brake rotor has beenbrought into the actual mounting state in this way, the pushrod 50 isrotated by actuating the motor 62 of the rotary device 61 and therotation is transmitted through the spline shaft 63 to the hub ring 2 ato rotate the brake rotor 13.

[0060] After the rotation of the brake rotor 13, by moving the tool rest64 parallel to the reference surface 4 a of the vehicle body mountingflange 4, the braking surfaces 13 a of the brake rotor 13 is cut withthe pair of cutters 66 of the cutting tool 65, of which the distancebetween the cutters has been adjusted beforehand.

[0061] As described above, by cutting the braking surfaces 13 a of thebrake rotor 13 with the wheel bearing assembly A supported in the actualmounting state, and with the tool rest 64 carrying the cutting tool 65positioned parallel to the reference surface 4a formed on the vehiclebody mounting flange 4, accumulated errors in which manufacturing errorsof the parts forming the wheel bearing assembly A have been accumulated,strains produced in the brake rotor 13 when mounting it, etc. areremoved. Thus it is possible to finish the braking surfaces 13 a topredetermined surfaces.

[0062] The cutting of the braking surfaces 13 a should be by dry-cuttingusing no cutting oil. By supplying compressed air into the air supplypassage 39 during cutting, the compressed air will flow along the outerperipheral surface of the outer member 1 and flow out from the opposedsurfaces of the spring collet 27 and the wheel-mounting flange 6. Thisprevents the occurance of trouble that chip produced by cutting adheresto the seals S of the wheel bearing assembly and causes damage to them.

[0063] Also, as shown by chain line of FIG. 2, suction nozzles 75 areprovided around the cutters 66 of the tool holders 67 a and 67 b andsuction force is applied to the suction nozzles 75 to suck chip. Thisprevents chip from adhering to the seals S of the wheel bearing assemblyA, causing damage to them.

[0064] After cutting of the braking surfaces 13 a of the brake rotor 13,the slider 71 of the linear slide 69 is retracted to retract the toolholder 67 b supported on the slider 71 relative to the fixed tool holder67 a. The tool rest 64 is then retracted.

[0065] After retraction of the tool rest 64, the pushrods 43 and 50 ofthe first pressing device 24 and the second pressing device 25 torelease clamping of the inner member 2 from both sides and pressing ofthe brake rotor 13 by the pressing member 52. The wheel bearing assemblyA with the brake rotor is removed from the cutting device.

[0066] In the embodiment shown in FIG. 2, description has been madetaking the wheel bearing assembly A with the brake rotor shown in FIG. 3as an example. But a wheel bearing assembly A with a brake rotor is notlimited thereto. It may be the wheel bearing assembly A for anon-driving wheel shown in FIG. 4.

[0067] The wheel bearing assembly A shown in FIG. 4 differs from the oneshown in FIG. 3 in that the inner member 2 comprises an axle 15 as afirst rotary member having a wheel-mounting flange 16 and a raceway 15 aon its outer periphery, and a raceway member 17 as a second rotarymember mounted on a small-diameter portion 15 b of the axle 15. For thesame parts as those of the wheel bearing assembly A shown in FIG. 3, thesame symbols are used and their description is omitted.

[0068] In the preparation for the cutting of the braking surfaces 13 aof the brake rotor 13 which is to be mounted to the wheel bearingassembly A, as shown in FIG. 5, the brake rotor 13 and a flange 18having a spline hole 19 are superposed on the wheel-mounting flange 16provided on the axle 15, the nuts 14 are brought into threadedengagement with the hub bolts 8 provided on the wheel-mounting flange16, and the nuts 14 are tightened with a predetermined torque toassemble the wheel bearing assembly A with the brake rotor in the actualmounted state.

[0069] In the cutting device shown in FIG. 2, the pressing member 52supported on the tip of the pushrod 50 of the second pressing device 25is removed beforehand. For the rotation of the brake rotor 13 to cut thebraking surfaces 13 a, while the pushrod 50 presses the flange 18, thespline shaft 63 at the tip of the pushrod 50 is inserted into the splinehole 19 of the flange 18 to transmit the rotation of the pushrod 50through the spline shaft 63 to the flange 18, thereby rotating the innermember 2 and the brake rotor 13.

[0070] As described above, according to this invention, by clamping withthe chuck device the cylindrical outer peripheral surface of the outermember positioned by the positioning member and advancing the pushrodsof two oppositely arranged pressing devices, the wheel bearing assemblywith the brake rotor can be retained in the actual mounting state. Also,it can be removed from the cutting device by retracting the pushrods ofthe pair of pressing devices and releasing the clamping by the chuckdevice. Thus, the wheel bearing assembly with the brake rotor can beattached and detached easily to and from the cutting device. Thuscutting of the braking surfaces of the brake rotor can be carried outefficiently.

What is claimed is:
 1. A method of cutting braking surfaces of a brakerotor of a wheel bearing assembly, said assembly comprising an outermember having a vehicle body-mounting flange on its outer periphery, aninner member having a wheel-mounting flange on its outer periphery,rolling elements disposed between said outer member and said innermember for rotatably supporting said inner member, and the brake rotorwhich is mounted to said wheel-mounting flange of said inner member, themethod comprising the steps of assembling the wheel bearing assemblywith the brake rotor in an actual mounted state, determining a mountingsurface of said vehicle body-mounting flange to be mounted on a vehiclebody as a reference surface, non-rotatably supporting said outer memberpositioned against said reference surface, clamping said inner memberwith a pair of oppositely arranged pressing members from both endsthereof with a pressing force corresponding to the clamping force in theactual mounted state, rotating said inner member and said brake rotorwhile maintaining the clamped state, and cutting the braking surfaces ofsaid brake rotor by moving a cutting tool in a direction parallel tosaid reference surface.
 2. The method as claimed in claim 1 whereincutting by said cutting tool is by dry-cutting.
 3. The method as claimedin claim 2 wherein said braking surfaces of the brake rotor is cut withcompressed air flowing from one end of said outer member along its outerperipheral surface.
 4. The method as claimed in claim 2 or 3 whereinsaid braking surfaces are cut while sucking chip formed by cutting.
 5. Acutting device for cutting braking surfaces of a brake rotor mounted ona wheel bearing assembly, said wheel bearing assembly comprising anouter member having a vehicle body-mounting flange on its outerperiphery, said vehicle body-mounting flange having a mounting surfaceto a vehicle body as a reference surface, an inner member having awheel-mounting flange on its outer periphery, and rolling elementsdisposed between said outer member and said inner member, said cuttingdevice comprising a positioning member for positioning said referencesurface on said vehicle body-mounting flange of said outer member, achuck device for clamping said outer member, a pair of pressing devicesfor pressing and clamping said inner member from both ends thereof witha pressing force corresponding to the clamping force in an actualmounted state, a rotary device for rotating said inner member, and atool rest carrying a cutting tool for cutting the braking surfaces ofsaid brake rotor and mounted so as to be movable in a direction parallelto said reference surface on said vehicle body-mounting flange of saidouter member.
 6. The cutting device as claimed in claim 5 wherein saidcutting tool has a pair of tool holders each carrying a cutter forcutting one of the braking surfaces on both sides of said brake rotor,one of said tool holders being fixed to said tool rest, while the otheris supported so as to be moved relative to said one tool holder.
 7. Thecutting device as claimed in claim 5 or 6 further comprising an airsupply means for supplying compressed air from one end of said outermember along its outer peripheral surface.
 8. The cutting device asclaimed in any of claim 5 -7 further comprising a suction means forsucking and removing chip formed by cutting said brake rotor.